1. Field of the Invention
The present invention relates in general to drug delivery devices used to deliver ionic medicaments through the skin or other tissues, and, more particularly, to fluid delivery assemblies for delivering a fluid to a bioelectrode element.
2. Background Art
Drug delivery devices have been known in the art for several years. Furthermore, drug delivery devices having fluid delivery assemblies for delivering fluid to bioelectrodes are likewise well known and are the subject of many United States Patents including: U.S. Pat. No. 4,878,775; U.S. Pat. No. 4,493,574; and U.S. Pat. No. 5,817,044.
U.S. Pat. No. 4,878,775 discloses a fluid transfer device having a rigid portion, a chamber containing microcapsules of fluid, and a layer of permeable material. The microcapsules are ruptured by placing pressure upon the rigid portion, expelling the fluid through the permeable material and onto the surface of application.
U.S. Pat. No. 4,493,574 discloses a dispenser package having a fault line or cut pattern scored into a relatively stiff material, to which a pouch containing a fluid is attached. The ends of the stiff material are then formed into a xe2x80x9cVxe2x80x9d shape breaking the pouch and delivering the fluid through one or more holes pre-cut in the fault line.
U.S. Pat. No. 5,817,044 discloses an iontophoretic drug delivery device with an electrode reservoir and drug reservoir, where a liner separates the two components. The liner must be peeled or ripped away, allowing fluid to flow from the drug reservoir to the electrode reservoir.
The present invention is directed to a fluid assembly for a bioelectrode for use in a drug delivery device, comprising a reservoir, having an interior region, containing a fluid therein; a barrier member associated with the fluid reservoir for precluding inadvertent release or migration of the fluid out of the reservoir, and means for breaking at least a portion of the barrier so as to allow release of fluid from the fluid reservoir. The breaking means may comprise an inert component positioned within the interior region of the fluid reservoir.
In a preferred embodiment of the invention, the reservoir includes means for facilitating depression of at least a portion of the reservoir. In this embodiment, the reservoir has a bottom region juxtaposed with the barrier member, and a top region. The depression means is preferably integrally associated with the top region of the reservoir. However, it is also contemplated that such a depression means comprise an external, or internal component attached to, or near the top region of the reservoir. For example, an additional piece of material, such as plastic, can be associated therewith to further facilitate depression.
In another preferred embodiment, at least a portion of the reservoir has a tensile strength greater than the tensile strength of the barrier.
In a preferred embodiment of the invention, the breaking means is freely positioned within the interior region of the reservoir. In such an embodiment, the breaking means is selected from the group of geometries consisting of spherical, cubical, tetrahedronal, octahedronal, dodecahedronal, icosahedronal, cylindrical, conical, ellipsoidal, toothed, circular, oval, triangular, rectangular, square, or polygonal configurations.
It is further contemplated that the interior region of the reservoir include at least one position retainment member. In such an embodiment, the position retainment member serves to keep the breaking component within a confined area within the reservoir.
In still another preferred embodiment of the invention, the breaking means is attached with at least a portion of the reservoir. Preferably, the reservoir has a top region, and the breaking means is attached with the top region.
In yet another preferred embodiment of the invention, the breaking means is attached with the barrier member. In this, as well as the other preferred embodiments, the breaking means may have a hardness greater than that of barrier member.
The present invention is also directed to a method for releasing a fluid from a fluid assembly to a receiving member of a drug delivery device. The method preferably comprises the steps of: (a) applying a force to an external surface of a fluid reservoir of the fluid assembly; (b) depressing at least a portion of the fluid reservoir upon application of the force; (c) forcing a breaking component located within an interior region of the fluid reservoir, toward and into contact with a barrier member, wherein the barrier member serves to preclude inadvertent migration and release of fluid out of the fluid reservoir; (d) breaking at least a portion of the barrier member with the breaking component; and (e) releasing fluid from within the fluid reservoir, past the barrier member, and toward and into contact with a receiving member.
Although the described method alludes to forcing the breaking component toward the barrier, the present invention is also directed to associating the breaking component with the barrier member, and forcing at least a portion of the fluid reservoir towards that breaking component to, in turn, break at least a portion of the barrier member therewith.
The invention will now be described with the reference to the following drawings, wherein:
FIG. 1 of the drawings is a perspective view of the present invention as attached with a drug delivery device;
FIGS. 2A and 2B of the drawings are cross-sectional views of a drug delivery device showing, among other things, the flexibility of associating one or more fluid assemblies with one or more receiving members;
FIG. 3 of the drawings is a cross-sectional view of a drug delivery device in operation;
FIG. 4 of the drawings is a cross-sectional view of an alternative embodiment of the drug delivery device of the present invention;
FIG. 5 of the drawings illustrates a number of possible geometric configurations for the construction of the breaking means; and
FIG. 6 of the drawings is a cross-sectional view of an alternative embodiment of the drug delivery device of the present invention.